Application Note...

PCS400 Pressure Calibration System

Application:

A new company in the medical industry had a requirement for a high accuracy pressure calibrator to perform calibrations on pressure sensors for a hemodialysis machine and to check peristaltic pumps. Another special application at this same company was to simulate blood pressure in a research project. This company designs and manufactures hemodialysis equipment for patients suffering from end stage renal disease, which is more commonly known as chronic kidney failure.

Challenge:

The challenge was to provide a versatile, high accuracy calibrator/controller that could address all of their pressure test, pressure calibration and research requirements.

Solution:

Two Mensor PCS400 Pressure Calibration Systems (with different pressure ranges) were chosen to: (1) insure the quality of their pressure sensors, (2) test the peristaltic pump and (3) perform research. The pressure ranges of the PCS400 in the first two applications is –atm to 100 psig. In the third application, a low pressure PCS400 is set at 120 mmHg to simulate human blood pressure, specifically the "upper number" or systolic pressure. The PCS400 is used to generate a pressure (that is equivalent to blood pressure), into a volume that is approximately 3 gallons (11 liters). This volume represents the equivalent volume of blood that is in the human body. The PCS400 is also used to simulate the inlet and outlet pressures of the dialysis pump. Since there can be negative pressures (or vacuum), the PCS400 has to be able to generate pressures as low as 300 to 500 mmHg vacuum. Changes in human blood pressure can vary by body movement by 30 to 60 mmHg. The PCS400 is able to generate a very stable pressure within a few tenths of a mmHg. The research test system consists of a Mensor PCS400, a temperature-controlled chamber, a fixed volume, a vacuum transducer and the associated pneumatic hardware.